/* ================================================================
   OCEANOGRAPHER GAURAV : water-column stylesheet
   The page descends from surface light to abyssal dark.
   All colours live in :root below. Change them once, they change
   everywhere.
   ================================================================ */

:root {
  /* Depth palette: surface to seafloor */
  --surface:      #E8F1F2;   /* pale hydrographic-chart blue */
  --thermocline:  #BFD9DC;   /* photic-zone blue-grey */
  --deep:         #14424E;   /* deep teal-navy */
  --abyssal:      #0B2833;   /* near-abyss */
  --floor:        #061820;   /* seafloor ink */

  /* Text and accents */
  --ink:          #14323D;   /* dark text on light panels */
  --foam:         #DCEBEC;   /* light text on dark panels */
  --contour:      #7FA8AE;   /* contour lines, rules, muted text */
  --buoy:         #D08A3C;   /* amber accent: links, markers */

  /* Type */
  --serif: 'Spectral', Georgia, serif;
  --mono:  'IBM Plex Mono', 'Courier New', monospace;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
}

body {
  font-family: var(--serif);
  font-weight: 400;
  color: var(--ink);
  background: var(--surface);
  line-height: 1.65;
}

/* ----------------------------------------------------------------
   NAVIGATION
   ---------------------------------------------------------------- */
.site-nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  background: color-mix(in srgb, var(--surface) 88%, transparent);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--contour);
}

.site-nav nav {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0.9rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-name {
  font-family: var(--mono);
  font-weight: 500;
  font-size: 0.85rem;
  letter-spacing: 0.18em;
  color: var(--ink);
  text-decoration: none;
}

.nav-links {
  display: flex;
  gap: 1.6rem;
  list-style: none;
}

.nav-links a {
  font-family: var(--mono);
  font-size: 0.78rem;
  letter-spacing: 0.06em;
  color: var(--ink);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  padding-bottom: 2px;
  transition: border-color 0.2s, color 0.2s;
}

.nav-links a:hover,
.nav-links a:focus-visible {
  color: var(--buoy);
  border-bottom-color: var(--buoy);
}

.nav-toggle { display: none; }

/* ----------------------------------------------------------------
   DEPTH RAIL (signature element)
   ---------------------------------------------------------------- */
.depth-rail {
  position: fixed;
  left: 1.4rem;
  top: 15vh;
  bottom: 8vh;
  width: 2px;
  z-index: 50;
}

.depth-line {
  position: absolute;
  inset: 0;
  background: linear-gradient(var(--contour), var(--buoy));
  opacity: 0.55;
}

.depth-marker {
  position: absolute;
  left: -5px;
  top: 0;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--buoy);
  box-shadow: 0 0 0 4px color-mix(in srgb, var(--buoy) 25%, transparent);
  transition: top 0.1s linear;
}

.depth-marker span {
  position: absolute;
  left: 20px;
  top: -4px;
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.05em;
  color: var(--buoy);
  white-space: nowrap;
}

/* ----------------------------------------------------------------
   PANELS: each darker than the last
   ---------------------------------------------------------------- */
.panel { padding: 7rem 1.5rem; position: relative; overflow: hidden; }
.wrap  { max-width: 900px; margin: 0 auto; }

.panel-surface     { background: var(--surface);     color: var(--ink);  min-height: 92vh; display: flex; align-items: center; }
.panel-thermocline { background: var(--thermocline); color: var(--ink); }
.panel-deep        { background: var(--deep);        color: var(--foam); }
.panel-abyssal     { background: var(--abyssal);     color: var(--foam); }
.panel-floor       { background: var(--floor);       color: var(--foam); }

.eyebrow {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.22em;
  color: var(--buoy);
  margin-bottom: 1.4rem;
}

h1 {
  font-size: clamp(2.8rem, 7vw, 5rem);
  font-weight: 300;
  letter-spacing: -0.015em;
  line-height: 1.05;
  margin-bottom: 1.4rem;
}

h2 {
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  font-weight: 300;
  font-style: italic;
  margin-bottom: 1.6rem;
}

h3 {
  font-size: 1.05rem;
  font-weight: 500;
  margin-bottom: 0.5rem;
}

/* ----------------------------------------------------------------
   HERO
   ---------------------------------------------------------------- */
.hero { position: relative; z-index: 2; }
/* Portrait as background element: bottom-anchored, behind the text,
   soft-fading at its left edge and into the contour zone below */
.hero-figure {
  position: absolute;
  right: clamp(2rem, 9vw, 12rem);
  bottom: 10;
  height: min(38%, 96vh);
  width: auto;
  z-index: 2;
  pointer-events: none;
  filter: saturate(0.9);

  -webkit-mask-image:
    linear-gradient(90deg, transparent 0%, black 18%),
    linear-gradient(180deg, black 78%, rgba(0,0,0,0.45) 100%);
  -webkit-mask-composite: source-in;

  mask-image:
    linear-gradient(90deg, transparent 0%, black 18%),
    linear-gradient(180deg, black 78%, rgba(0,0,0,0.45) 100%);
  mask-composite: intersect;
}
.hero-sub {
  font-size: clamp(1.15rem, 2.4vw, 1.45rem);
  font-weight: 300;
  max-width: 34em;
  margin-bottom: 1rem;
}

.hero-detail {
  font-family: var(--mono);
  font-size: 0.82rem;
  color: color-mix(in srgb, var(--ink) 70%, transparent);
  margin-bottom: 3rem;
}

.descend-cue {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  font-family: var(--mono);
  font-size: 0.78rem;
  letter-spacing: 0.15em;
  color: var(--ink);
  text-decoration: none;
}

.descend-cue svg { animation: bob 2.4s ease-in-out infinite; }

@keyframes bob {
  0%, 100% { transform: translateY(0); }
  50%      { transform: translateY(6px); }
}

.contours {
  position: absolute;
  bottom: 0; left: 0;
  width: 100%; height: 220px;
  z-index: 1;
}

.contours path {
  fill: none;
  stroke: var(--contour);
  stroke-width: 1.2;
  opacity: 0.6;
}

/* ----------------------------------------------------------------
   RESEARCH
   ---------------------------------------------------------------- */
.lede {
  font-size: 1.15rem;
  font-weight: 300;
  max-width: 38em;
  margin-bottom: 3rem;
}

.research-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.4rem;
}

.card {
  border: 1px solid var(--contour);
  padding: 1.6rem;
  background: color-mix(in srgb, var(--surface) 45%, transparent);
}

.card p { font-size: 0.95rem; }

/* ----------------------------------------------------------------
   PUBLICATIONS
   ---------------------------------------------------------------- */
.pub-list { list-style: none; }

.pub-list li {
  display: flex;
  gap: 1.6rem;
  padding: 1.2rem 0;
  border-bottom: 1px solid color-mix(in srgb, var(--contour) 40%, transparent);
}

.pub-year {
  font-family: var(--mono);
  font-size: 0.8rem;
  color: var(--buoy);
  min-width: 3.2em;
  padding-top: 0.25em;
}

.pub-title { font-size: 1.05rem; font-weight: 500; }

.pub-meta {
  font-family: var(--mono);
  font-size: 0.75rem;
  color: color-mix(in srgb, var(--foam) 65%, transparent);
  margin-top: 0.25rem;
}

.pub-meta a, .aside-note a, .beyond-grid a, .contact-line a, .contact-links a {
  color: var(--buoy);
  text-decoration: none;
  border-bottom: 1px solid color-mix(in srgb, var(--buoy) 45%, transparent);
}

.pub-meta a:hover, .aside-note a:hover, .beyond-grid a:hover,
.contact-line a:hover, .contact-links a:hover {
  border-bottom-color: var(--buoy);
}

.aside-note {
  margin-top: 2rem;
  font-size: 0.9rem;
  color: color-mix(in srgb, var(--foam) 75%, transparent);
}

/* ----------------------------------------------------------------
   BEYOND
   ---------------------------------------------------------------- */
.beyond-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 2.2rem 2.8rem;
}

.beyond-grid p { font-size: 0.95rem; color: color-mix(in srgb, var(--foam) 85%, transparent); }

/* ----------------------------------------------------------------
   CONTACT / FOOTER
   ---------------------------------------------------------------- */
.contact-line { font-size: 1.2rem; margin-bottom: 1.6rem; }

.contact-links {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 1.6rem;
  font-family: var(--mono);
  font-size: 0.82rem;
  margin-bottom: 4rem;
}

footer p {
  font-family: var(--mono);
  font-size: 0.7rem;
  color: color-mix(in srgb, var(--foam) 45%, transparent);
}

/* ----------------------------------------------------------------
   MOBILE
   ---------------------------------------------------------------- */
@media (max-width: 960px) {
  .hero-figure { display: none; }
}
@media (max-width: 760px) {
  .depth-rail { display: none; }

  .panel { padding: 5rem 1.25rem; }

  .nav-toggle {
    display: flex;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 6px;
  }

  .nav-toggle span {
    width: 22px; height: 2px;
    background: var(--ink);
  }

  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0; right: 0;
    flex-direction: column;
    gap: 0;
    background: var(--surface);
    border-bottom: 1px solid var(--contour);
    padding: 0.5rem 0;
  }

  .nav-links.open { display: flex; }

  .nav-links li a {
    display: block;
    padding: 0.9rem 1.5rem;
    border-bottom: none;
  }
}